Electrical contact making and breaking device



A. P. YOUNG. ELECTRICAL CONTACT MAKING AND BREAKING DEVICE.

APPLICATION FILED MAR. I0. I9|9.

Inventor' Ahur- P. goung, His Attorney.

lPatented Nov. 7, 1922.

UNITED STATES PATENT OFFICE.

ARTHUR PRIMROSE YOUNG, 0F KENILWORTH, ENGLAND, ASSIGNOR T0 GENERAL ELECTRIC COMTANY, A CORPORATION 0F NEW YORK.'

ELECTRICAL CONTACT MAKING AND BREAKING DEVICE.

Application filed March 10, 1919. Serial No. 281,886.

T 0 all whom t may concern Be it known that I, ARTHUR PRIMROSE YOUNG, a subject of the King of Great Britain, residing at Kenilworth, county of WIarWiCkShire, England, have invented certain new and useful Improvements in Electrical Contact Making and Breaking Devices` of which the following is a specification.

The present invent-ion relates to apparatus for making and breaking electric circuits and more particularly to apparatus for use in a circuit which has to be made and broken a large number of times in quick succession. Contact breakers as used in such circuits usually' consist of a pivoted lever and a cam, one end of the lever being held in contact with the cam surface by means of a spring, while the other end carries a contact adapted to cooperate with a fixed contact to make and break the circuit when the cam is rotated. Such contact breakers are well known and operate satisfactorily up to a certain critical speed which depends on the spring strength, the moment of inertia and the acceleration of the moving parts. Beyond this critical speed they do not work satisfactorily owing to the fact that the lever will not remain in constant contact wit-h the cam.

In still another form of contact breaker the cooperatingr contacts are mounted on two pivoted levers arranged so they engage opposite sides of an actuating cam. Each lever is engaged by a spring so that they are biased to the position in which the contacts are closed, the cam being arranged to simultaneously move the lever in opposite directions to separate the contacts.

This latter form of Contact making and breaking device has the advantage that the critical speed at which it will operate satisfactorily is raised to such an extent that it will operate at speeds substantially greater than that obtained by contact breakers such as above described. As the critical speed for given conditions is dependent on the acceleration of the moving parts, it will be obvious that if this movement is reduced the critical speed can be raised. The amount of this movement is seldom less than about twelve thousandths of an inch. so that this is the maximum space separating the fixed and moving conta-cts during operation, and if both the contacts are simultaneously moved by the cam in opposite directions, the

movement of each contact is only half what would be required were either stationary.

T he objectif my invention is to provide an lmproved contact making and breaking device of the latter form, which is sim le and compact in construction, and Whlch operates at a substantially higher critical speed than heretofore attained in such devices. In my invention the two levers are preferably U-shaped in form and are pivotally mounted intermediate their ends.

Other features of novelty which characterize my invention will appear in the course of the following description and will be definitely pointed out in the appended claims.

The invention will be best understood by referring to the accompanying drawings, in which Fig. l is an end elevation and Fig. 2 a side elevation, partly in section, of my contact making and breaking device applied to a magneto electric machine.

In the drawings, the cooperating contents l and 2 are shown mounted on the adjacent limbs 8 and 4 of two substantially U-shaped levers arranged side by side and preferably pivotally mounted at the bend on the pivots 5 and 6. Leaf springs 7 and 8 are connected to the inner adjacent limbs of the U-shaped levers in such a manner that the levers are normally pressed toward each other to close t-he contacts. The outer limbs 3 and 4. of the U-shaped levers are arranged so that they engage opposite sides of the four point cam 9 which is rigidly secured to the shaft l0 of the magneto electric machine. For the sake of compactness these outer limbs 3 and 4 are preferably displaced from the plane of the inner adjacent limbs and in the drawings are shown as set in such a plane that the cam is located immediately behind the contact-carrying limbs, and are provided with fibre heels 11 and 12 at the points where they engage the cam. Buffer springs 18 and 14 are arranged to engage the outer limbs 3 and 4 respectively and assist the leaf springs 7 and 8 in holding the levers in contact with the cam so that as the cam rotates they follow the cam surface, the Inotion being transmitted to the contact-carrying limbs.

The lever 3 3 is mounted on a block 15 which is insulated from the base as shown in Fig. 2 and the contact l may be electrically connected to the winding of the machine through the leaf spring 7. The other lever 4-4 is mounted on a block 16 directly attached to the base and is therefore, connected to ground through the frame of the machine.

Means such as an adjusting screw 17 in a lug 18 projecting from the base is pro.- vided as a stop to be engaged by a projection 19 on the outer end of limb 3 of lever 3--3 and this projection 19 being held in contact with the screw 17 by the springs 7 and 13 insures that the point of engagement of the contacts 1 and 2 will remain fixed in space.

It is desirable that the pressure exerted by the springs 7 and 13 be slightly greater than that exerted by the springs 8 and 14 so as to insure that the projection 19 will be held in engagement with the adjustin screw 17.

l aving thus illustrated and described wh-at I now consider the best embodiment of my invention, it is obvious that .the construction and arrangement of parts may be modified without departing from the spirit of my invention, the scope of which is set forth in the appended claims.

What I claim as new and desire to secure by Letters Patent of the United States, 1s,-

l. A contact making and breaking device comprising a pair of pivoted levers, cooperating contacts mounted one on each lever, said levers being normally spring pressed to contact closing position, a stop for one of said levers whereby the point of said levers, each pivotally mounted intermediate its ends, said levers being normally spring pressed to contact closing position, and an actuating cam arranged to engage the other corresponding limbs of said levers and` adapted to simultaneously move said levers in opposite directions to separate said contacts.

3. A contact ma ing and breaking device comprising a pair f substantially U-shaped levers pivotally mounted side by side, cooperating contacts mounted 0n corresponding limbs of said levers, said levers being normallyv spring pressed to contact closing position, a stop for one of said levers whereby the point of engagement of said contacts is fixed, and an actuating cam arranged to engage the other corresponding limbs of said levers and adapted to simultaneously move said levers in opposite directions to separate said contacts.

4. A contact making and breaking device comprising la pair of substantially U-shaped levers-pivotally mounted side by side, cooperating contacts mounted on the adjacent limbs of said Ushaped levers, the outer limbs of said levers being displaced from the plane of the two adjacent contact-carrying limbs, said levers being normally spring pressed to contact closing position, and an actuating cam engaging the outer limbs of said levers and adapted to simultaneously move said levers in opposite directions to separate said contacts.

5. A contact making and breaking device comprising a pair of substantially U-shaped levers pivotally mounted side by side, cooperating contacts mounted on the adjacent limbs of said U-shaped levers, the outer limbs of said levers being displaced from the plane of the two adjacent contact-carrying limbs, said levers being normally spring pressed to contact closing position, a stop for one of said levers whereby the point of engagement of said contacts 1s ixed, and an actuating cam engaging the outer limbs of said levers and adapted to simultaneously move said levers in opposite directions to separate said contacts.

6. A contact making and breaking device comprising a pair of substantially U-shaped levers mounted side by side and each pivoted at its bend, cooperating contacts mounted on the adjacent limbs of said U-shaped levers, the outer limbs of said levers being displaced from the plane of the two adjacent contact-carrying limbs, said levers being normally spring pressed to contact-closing position, a stop for one of said levers whereby the point of engagement of said contacts is fixed, and an actuating cam engagin the outer limbs of said levers and adapted to simultaneously move said levers in opposite directions to separate said contacts.

In witness whereof, l have hereunto set my hand this fourteenth day of February,

ARTHUR PRIME-OSE YOUNG. lVitnesses J oHN HALFoRD, DOROTHY WHITE. 

